1. Field of the Invention
This invention relates to data processing systems. More particularly, this invention relates to data processing systems including a decompression mechanism for forming program instructions from compressed instruction data.
There are several known data processing systems using compressed instruction data which is decompressed into program instructions prior to those program instructions being executed. One example of such a system is that of MIPS Corporation which uses compressed memory pages of program instruction words which are decompressed under operating system control using special purpose hardware when program instructions within those pages are first accessed. Such systems are advantageous in that they reduce the program instruction storage space requirements.
A disadvantage with program instruction compression techniques, such as that discussed above, are that they require the operating systems to control the required decompression and the data processing circuits using the program instructions can require modification to cope with the decompression requirements.
2. Description of the Prior Art
It is also known to provide instruction translation caches in which instructions stored in a main memory are translated into a different form which is then stored within a cache memory. Those cached translated instructions can then be executed by a processor core. Examples of such systems are the processors produced by Transmeta.